1. Technical Field
This application relates to a surgical retractor, and more particularly, to a surgical retractor which facilitates the harvesting of veins.
2. Background of the Related Art
In certain surgical procedures, it is necessary to remove an artery or vein from the patient. For example, in coronary artery bypass surgery (CABG), to re-route the blood flow to or from the heart to bypass a blockage in the coronary artery, an artery or vein is harvested from the patient and connected to the coronary artery to enable the unobstructed flow of blood.
In certain instances, e.g. when only a short graft is required, the mammary artery can be harvested and used for CABG. However, the mammary artery is oftentimes of insufficient length. Therefore, the patient's saphenous vein is most often utilized. The saphenous vein runs the length of the leg and is about 1/4 to 1 inch below the skin. The most common method of removing the saphenous vein currently performed by surgeons involves making an incision in the patient's leg extending the length of the section of the vein to be removed. Frequently, this requires an incision running the entire length of the leg, from the ankle to the groin, which can be over 40 inches in length. Once the leg is opened in this manner, the surgeon, utilizing a light source supported on headgear or a headband, dissects the vein from the surrounding tissue and ligates and severs the vein from its numerous branches along its length. The vein is then cut at both ends and removed from the patient for use as a graft attached to the coronary artery or aorta. After removal of the vein, the leg incision is sutured.
Such formation of a large leg incision has many disadvantages. It is time consuming, complicates the procedure, creates a large scar, and increases the risk of infection and skin necrosis. It also adds to the expense of the procedure by requiring additional surgeon time to close the leg incision. Moreover, it increases the patient's discomfort and prolongs the patient's recovery time. In fact, the recovery time from the leg incision can take even longer than the recovery time from the chest incision from the heart surgery.
The need for a less invasive method and instrumentation to remove the saphenous vein is recognized in the field. For example, in U.K. Patent No. 2,082,459, an apparatus is disclosed for harvesting the saphenous vein utilizing two small incisions. A center rod is inserted into the lumen of the vein, and the tubular body having a series cutting blades is introduced over the center rod and passed along the vein to cut the tributaries and fatty tissue around the vein. U.S. Pat. No. 4,793,346 to Mindlich discloses an apparatus which has a pair of knife blades extending from an elongate plastic tube. The tube has an inner diameter larger than the outer diameter of the vein. In use, the tube is inserted through an incision, and guided over the vein by a flexible guide which is inserted through the vein. The tube is rotated as it is advanced so that the knife blades can sever the vein branches. Electrically conductive wires are coupled to the knife blades to cauterize the severed end of the branches. U.S. Pat. No. 5,373,840 to Knighton discloses an endoscope and method for vein removal under visualization. A dissecting tool is inserted through one of the endoscope channels to separate the blood vessel from the connective tissue and a forceps is inserted through a second channel to hold the vessel during the procedure. The endoscope is inserted through a small incision and the dissecting tool is advanced along the vein. When a side branch is encountered, the dissection tool is removed and a ligating-cutting tool is inserted through the channel to sever the side branch.
Each of the instruments of the prior art described above are complex and expensive. Furthermore, they require the procedure to be performed in a tight working space as the vein is not separated from the surrounding tissue and the instruments are wedged between the vein and the tissue.
It would be advantageous to provide an apparatus which could minimally invasively separate the skin (and subcutaneous tissue) from the vein to enable dissecting and ligating instrumentation to be inserted through small incisions to facilitate removal of the saphenous vein. It would also be advantageous to equip such apparatus with illumination capabilities to enable the surgeon to better visualize the vein as it is dissected. This would not only eliminate the need for the surgeon to wear cumbersome head gear, but would avoid the expense involved with the use of an endoscope as well as avoid the additional time required for the constant withdrawal and reinsertion of the instruments through the endoscope's working channels.